Another thing you may want to keep in mind is that flash cards don't really retain their data forever. Due to the nature of the technology, they leak power and will start to erase themselves over time. I wouldn't worry about the cards wearing out, since this is the Amiga filesystem we're discussing, but data retention may be a bit iffy. Make sure you have a decent backup solution. Hard drives are far, far better at data retension, though you should at least power up a HD once a year to help prevent it from seizing.
I hear a particularlly good flash will keep data for 10 years, but consumer CF cards and the like probably don't last that long. In theory, the larger the card (the smaller the manufacturing process), the faster it leaks.
I use a small SSD as a boot drive for my PC, and a really slow laptop drive for data, temp, and swap. Write cycles don't bother me too much, because technically the drive should still be readable, but I wouldn't trust a SSD at all for long-term storage.
I thought about getting a CF card, but settled on replacing my 85MB hard drive with a new 4200 RPM 20GB. The heat and noise difference is incredible. I have an A1200 running on stock IDE, so a faster drive makes no sense. I'd imagine that a CF card wouldn't be faster, either.
